: Theoretical treatment of Cooper pairing and the properties of superfluid Helium.
: It provides what many consider the clearest introduction to the formal use of Green's functions and Feynman diagrams in many-body systems. Zero to Finite Temperature : Theoretical treatment of Cooper pairing and the
[ \chi^(0)(\mathbfq,\omega)=\frac2V\sum_\mathbfk \fracn_F(\epsilon_\mathbfk)-n_F(\epsilon_\mathbfk+\mathbfq)\hbar\omega + i0^+ + \epsilon_\mathbfk-\epsilon_\mathbfk+\mathbfq, ] : Theoretical treatment of Cooper pairing and the